Autism spectrum disorder is a developmental disability that results in behavioral and social changes, including communication. The condition affects many more boys than girls.

Children whose siblings have autism spectrum disorder are also at increased risk of conditions such as developmental delay, attention deficit and intellectual disability. Taking prenatal vitamins as folic acid supplements during the first month of pregnancy is associated with a lower risk of developing autism in children who are at high risk for the disorder, according to a new study. The researchers at University of California, Davis believe that it’s the first study to prove this.

The researchers evaluated hundreds children's development. Of the children whose mothers took prenatal vitamins in the first month of the pregnancy, 14.1% went on to develop autism, compared with 32.7% in children whose mothers did not. Taking prenatal vitamins early was also associated with less severe symptoms and higher cognitive scores in children who were ultimately diagnosed with autism. “In highly genetically susceptible families where they’re already affected by autism, our study suggests there might be a way to … mitigate that risk,” said Rebecca Schmidt, co-author of the study. Schmidt said the findings reinforce the importance of prenatal care, both before and during pregnancy.